V. In roller coaster operation:
To delay the dispatch of a train for as
long as possible without causing a cascade effect. Usually done after adding and empty train after it has been at rest.
A fresh train will not move as fast because the wheels are
cold and need to move to generate the friction required for maximum speed. For this reason the "hot" fully
loaded train behind it
may catch up to it during the ride. different types of Coasters require some trains to be sandbagged more than once to allow for the preceding unit to achieve maximum velocity.
The new kid forgot to sandbag the train on main, now it's stuck in
safety 1, and the lead has to supervise adding the fifth train for
EVERYONE.
Thunder Mountain only requires a train to be sandbagged once, while Space Mountain
may require a "rocket" to be sandbagged up to three times.